论文标题
通过旅行热浪在对流系统中产生的区域流量
Generation of zonal flows in convective systems by travelling thermal waves
论文作者
论文摘要
这项工作探讨了在流体层表面上应用的热热波的影响，对2D和3D对流系统中全球流量结构的形成。对于雷利数字（$ 10^3 \ leq ra \ leq 10^7 $）和热浪频率（$ 10^{ - 4} \ leq oqω\ leq 10^{0} $），我们调查有和没有强加的平均温度梯度的流量。我们的结果证实，行进的热波会导致纬向流，即强烈的水平流。我们表明，扩散占主导地位的区域流纯粹是由雷诺应力驱动的，始终逆行行进，而在对流中占主导地位，平均流动对流是由倾斜的对流细胞引起的，这通常会导致阶段平均层次流动。通过直接的数值模拟，我们验证了对扩散统治的理论预测。此外，我们利用线性稳定性分析并解释了对流单元模式的存在。我们广泛的3D模拟支持2D流的结果，从而证实了研究结果与地质和天体物理系统的相关性。
This work addresses the effect of travelling thermal waves applied at the fluid layer surface, on the formation of global flow structures in 2D and 3D convective systems. For a broad range of Rayleigh numbers ($10^3\leq Ra \leq 10^7$) and thermal wave frequencies ($10^{-4}\leq Ω\leq 10^{0}$), we investigate flows with and without imposed mean temperature gradients. Our results confirm that the travelling thermal waves can cause zonal flows, i.e. strong mean horizontal flows. We show that the zonal flows in diffusion dominated regimes are driven purely by the Reynolds stresses, always travelling retrograde, while in convection dominated regimes, mean flow advection, caused by tilted convection cells, becomes dominant, which generally leads to prograde mean zonal flows. By means of direct numerical simulations we validate theoretical predictions made for the diffusion dominated regime. Furthermore, we make use of the linear stability analysis and explain the existence of the tilted convection cell mode. Our extensive 3D simulations support the results for 2D flows and thus confirm the relevance of the findings for geopyhsical and astrophysical systems.
